Switch



1959 w; w. MUMFORD m-AL 2,868,920

SWITCH Filed Au 1, 1955 FIG. 2

INVENTORS W/LL/AM I4. MUM/ ORD ALBERT J. NEWLA/VD ATTOR VE/ United States Patent 9 SWITCH William W. Mumford, Park "Ridge, and Albert J. Newland, Glen Rock, N. J., assignors to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application August I, 1955-, Serial No. 525,421

1 Claim. (Cl. 200-87) Thisinvention relates generally to a switch for electric circuits.

{in object of the present invention is to provide a novel switch that visibly indicates its operating condition by the position of a handle which hasacentered or oii position and an angu-larly displaced or on position; the switch being held in the on condition by magnetic attraction that is produced by the closing of a circuit when the handle is displaced to the on position and being returned to the oil condition manually upon overpowermg the magnetic attraction and returned to the off condltion automatically upon ,deenergization of the circuit producing the magnetic attraction.

\nother object is to provide a switch having a novel spring arrangement for returning the switch from an on position to an ofi position.

A further object is to provide aswitch having electromagnetic holding means for holding the switch in a predetermined-position. The foregoing and otherobjects and advantages of the invention will appear" more fully hereinafter from a consideration of the detailed description which follows, taken together wit-h the accompanying drawing wherein two embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, thatthe drawing is forthepurpose of illustration and description only, and is not-intended as a definition of the limits of the invention.

In the single sheet of drawing wherein like parts are marked alike:

Figure 1 is an elevational view of the novel switch of the present invention, with portions of the housing removed, and

Figure 2 is an elevational view of another embodiment of the novel switch of the present invention with portions of the housing removed.

Turning now to Figure 1 for a more detailed description of the invention, the frame of the novel switch has fixed thereto an electromagnet comprised generally of a pair of horseshoe-shaped iron bars 12 (only one being visible in the drawing) spaced on opposite sides of a coil 14. Also fixed to the frame and spaced between bars 12 at opposite sides of the frame are a pair of microswitches 16 and 18 which are connected to coil 14 in a suitable manner (not shown) and to an electric circuit to be controlled. Depressing plunger or operating button 20 or 21 of these microswitches closes the circuit from a suitable source of electrical energy (not shown) to a control circuit and to coil 14. The encrgization of coil 14 magnetizes bars 12.

The actuator for selectively operating one of the two switches 16 and 18 is a lever 23 which, at a point intermediate its length, is pivoted to frame 10 by a pin 25. One end 27 is shaped to provide a handle and the other end is bifurcated to mount an armature 28 therein. The armature is floatedly held in position by a pair of coacting semicircular springs B.

The displacement of handle 27 in either direction from a center position depresses contact 20 or 21 and closes the circuit for energizing coil 14. This magnetizes iron bars 12, and the magnetic attraction between these bars and armature 28 holds the lever in its displaced position. This magnetic attraction between bars 12 and armature 28 holds the switch in its on position but does not provide a positive lock. Thus, to return the switch manually to its centered position or off position, the magnetic attraction may be overcome manually. Then after a small disengagement of the lever from microswitch 16 or 18 so that contact 20 or 21 is no longer depressed, the contact opens the circuit to coil 14 and demagnetizes bars 12.

As is well known, a magnet requires a greater amount of energy to bring an armature into engagement with the magnet than it requires to hold the armature in engagement thereafter. The adidtional power, when not required, is dissipated as heat. The engagement of the armature and magnet is accomplished manually in the novel device of the present invention, and only a small amount of energy required to hold thearmature in engagernent with the magnet. Thus, unnecessary power con sumption is avoided. and additional provisions for heat dissipation are unnecessary when. banks of the switches are enclosed within small areas.

The novel switch of the present invention is also provided with an arrangement of rollers 29 and springs 31 for returning the switch to its centered or cit position upon deenergization of the circuit energizing coil 14. The pair of rollers 29 are journalled on the opposite side of lever 23 and coact with the pair of springs 31 (only one roller and spring being visible in Figure l). Springs 31 are flat and generally V-shaped with aninwardly Zbent U-shaped portion 32 at the normal point of the V. One end 33 of each spring is fixed and the other end 34 slides on frame 10 as the springs are flexed.

Springs 31 are normally slightly flexed so that rollers 29 are held at rest in the U-shaped portion or detent 32 when lever 23 is in the centered position.

When lever 23 is in the centered position, rollers 29 rest in the detents 32. As the spring is slightly flexed at this time, the lever is held in the centered position. Displacement of lever 23 from the centered position causes rollers 29 to further stress springs 31, and the bias provided by the springs tends to return the rollers to detent position. Thus, if coil 14 be deenergized when armature 28 and bars 12 are in engagement, bars 12 are demagnetized and the bias of springs 31 returns the rollers to detent and lever 23 to centered or off position.

If desired, the switch portions may be totally enclosed in container frame 10, and a rubber sleeve 42 may be utilized to complete the seal.

The switch described above is movable in either direction from the centered position. However, in some types of systems, it is necessary that the switch be moved only in one direction from centered position. Such a switch is shown in the embodiment of Figure 2.

Turning to Figure 2, an electromagnet comprising a pair of l.-shaped iron bars 59 and an energizing coil 52 is suitably fixed to frame 53. Pivo-tally connected to the frame by pin 34- is a bent lever 55 having one end 56 shaped to provide a handle for manual operation and the other end 57 bifurcated to receive an armature 60. Lever 55 also carries a bent spring 61 for actuating contact 63 of a microswitch 64 which is connected to a suitable source of excitation and to coil 52. Depressing contact 63 completes a circuit to energize coil 52 and magnetize bars 50 to maintain the switch member in a displaced position.

In a manner similar to that described above for Figure 1, the magnetic attraction of bars 5i and armature 60 may be overcome manually to return the switch to o-tt'" position. Also the switch is returned automatically to an off" position from an on position upon deenergization of the circuit either due to a circuit failure or to the opening of the circuit externally at some other location. To this end, a pair of springs 65 are fixed to frame 53 and a pair of coacting rollers 67 (only one roller and spring showing) are journalled on lever 55. These springs have a detent 66 for receiving the rollers 67 when the switch is in the position as shown in heavy lines. The springs are secured to the frame 53 by fastener 68.

When the switch lever 55 is in the position shown in dotted lines, the springs continually urge the lever to return to the detent position.

The switch as illustrated by solid lines is in the off position and the electromagnet is deenergized. However, moving handle 55 to the angular position shown in dotted lines causes the bent spring 61 to depress microswitch contact 63 to close the circuit for energizing the electromagnet, and the magnetic force produced by the energization of coil 52 thereafter holds the switch in the displaced position. Should a loss of energization occur, springs 65 return the switch lever to the solid line position.

The foregoing has presented a novel switch which in dicates visibility its position the operative condition of the circuits to controller, that is, whether it is on or off. The switch is held in an off position by a spring and a detent arrangement and in an on position by an electromagnet which is energized when the switch is moved to an on position. The engagement of the armature and magnet of the electromagnet is accomplished manually so that the magnet need only be the size required to maintain this engagement. When the coil producing the magnetic attraction is deenergized, the switch is returned to the off position automatically.

The magnetic attraction may also be manually overpowered to return the switch to an o position.

Although only two embodiments of the invention have been illustrated and described in detail, it is to be expressly understood that invention is not limited thereto. Various changes can be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as will now be understood by those skilled in the art.

What is claimed is:

A switch comprising a casing, a lever having end portions, means intermediate the end portions to pivotally mount the lever in said casing, said lever including one of said end portions positioned externally of said casing to provide an operating handle for the lever, an armature positioned interiorly of the casing and carried by the other end portion of said lever, a bowed spring member secured at one end to said casing and having a detent portion intermediate the ends thereof, roller means normally bearing on said detent portion and carried by said lever at a position intermediate the pivotal mounting means and the other end portion of said lever, said roller means stressing said spring member as the lever is displaced from normal position so that said spring member continually urges the lever to return to the normal position, switch means including a pair of switch devices selectively actuated When said lever is displaced a predetermined amount, said lever being manually operable at said handle in such a manner that the other end portion of the lever may be displaceable from the normal position in one sense to actuate one of said switch devices and in an opposite sense to actuate another of said switch devices, a U-shaped magnetic member having opposite arm portion and an excitation winding energized upon the aforesaid actuating of any one of said switch devices, the armature carried by said other end portion of said lever being arranged to cooperate with one arm portion of said magnetic member upon displacement of the lever in said one sense and with the other arm portion of said magnetic member upon displacement of the lever in said opposite sense so that said magnetic member thereby maintains said lever in a displaced position, and the bowed spring member biases said lever from said displaced position to said normal position upon deenergization of said excitation Winding.

References Cited in the file of this patent UNITED STATES PATENTS 423,891 Barriett Mar. 18, 1890 690,405 Darlington Jan. 7, 1902 692,217 Sundh Jan. 28, 1902 729,762 Harthan June 2, 1903 914,878 Read Mar. 9, 1909 992,009 Lang May 9, 1911 1,620,456 Gallus et a1. Mar. 8, 1927 1,647,663 Pollock Nov. 1, 1927 1,749,169 Swartwout Mar. 4, 1930 2,119,450 Trautner May 31, 1938 2,334,901 Bullerjahn Nov. 23, 1943 2,440,943 Gonsett et al. May 4, 1948 2,521,468 Lodge Sept. 5, 1950 2,763,737 Barber Sept. 18, 1956 UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,868,920 January 13, 1959 William W. Mumford et al.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4:, line 21, for actuating read actuation. Signed and sealed this 28th day of April 1959.

Attest: T. B. MORROW, ROBERT C. WATSON, Attesting Ofii'ver. aommz'ssz'oner of Patents.

UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,868,920 January 13, 1959 William W. Mumford et 91.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 21, for actuating read --actuation. Signed and sealed this 28th day of April 1959.

Attest: T. B. MORROW, ROBERT C. WATSON, Attesting Ofioer. Commissioner of Patents. 

